Aliphatic hyperbranched polyester: a new building block in the construction of multifunctional nanoparticles and nanocomposites

Core-Tunable Dendritic Polymer: A Folate-Guided Theranostic Nanoplatform for Drug Delivery Applications

Clinical application of anticancer drugs is mostly limited due to their hydrophobic nature, which often results in lower bioavailability and lesser retention in systemic circulation. Despite extensive research on the development of targeted drug delivery systems for cancer treatment, delivery of hydrophobic therapeutic drugs to tumor cells remains a major challenge in the field. To address these concerns, we have precisely engineered a new hyperbranched polymer for the targeted delivery of hydrophobic drugs by using a malonic acid-based A2B monomer and 1,6-hexanediol. The choice of monomer systems in our design allows for the formation of higher molecular weight polymers with hydrophobic cavities for the efficient encapsulation of therapeutic drugs that exhibit poor water solubility. Using several experimental techniques such as NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform-infrared (FT-IR), and gel permeation chromatography (GPC), the synthesized polymer was characterized, which indicated its dendritic structure, thermal stability, and amorphous nature, making it suitable as a drug delivery system. Following characterizations, theranostic nanoplatforms were formulated using a one-pot solvent diffusion method to coencapsulate hydrophobic drugs, BQU57 and doxorubicin. To achieve targeted delivery of loaded therapeutic drugs in A549 cancer cells, the surface of the polymeric nanoparticle was conjugated with folic acid. The therapeutic efficacy of the delivery system was determined by various cell-based in vitro experiments, including cytotoxicity, cell internalizations, reactive oxygen species (ROS), apoptosis, migration, and comet assays. Overall, findings from this study indicate that the synthesized dendritic polymer is a promising carrier for hydrophobic anticancer drugs with higher biocompatibility, stability, and therapeutic efficacy for applications in cancer therapy.

Dendritic Solid Polymer Electrolytes: A New Paradigm for High-Performance Lithium-Based Batteries

Li-ions battery is widely used and recognized, but its energy density based on organic electrolytes has approached the theoretical upper limit, while the use of organic electrolytes also brings some safety hazards (leakage and flammability). Polymer electrolytes (PEs) are expected to fundamentally solve the safety problem and improve energy density. Therefore, Li-ions battery based on solid PE has become a research hotspot in recent years. However, low ionic conductivity and poor mechanical properties, as well as a narrow electrochemical window limit its further development. Dendritic PEs with unique topology structure has low crystallinity, high segmental mobility, and reduced chain entanglement, providing a new avenue for designing high-performance PEs. In this review, the basic concept and synthetic chemistry of dendritic polymers are first introduced. Then, this story will turn to how to balance the mechanical properties, ionic conductivity, and electrochemical stability of dendritic PEs from synthetic chemistry. In addition, accomplishments on dendritic PEs based on different synthesis strategies and recent advances in battery applications are summarized and discussed. Subsequently, the ionic transport mechanism and interfacial interaction are deeply analyzed. In the end, the challenges and prospects are outlined to promote further development in this booming field.

Macromolecules Absorbed from Influenza Infection-Based Sera Modulate the Cellular Uptake of Polymeric Nanoparticles

Optimizing the biological identity of nanoparticles (NPs) for efficient tumor uptake remains challenging. The controlled formation of a protein corona on NPs through protein absorption from biofluids could favor a biological identity that enables tumor accumulation. To increase the diversity of proteins absorbed by NPs, sera derived from Influenza A virus (IAV)-infected mice were used to pre-coat NPs formed using a hyperbranched polyester polymer (HBPE-NPs). HBPE-NPs, encapsulating a tracking dye or cancer drug, were treated with sera from days 3-6 of IAV infection (VS3-6), and uptake of HBPE-NPs by breast cancer cells was examined. Cancer cells demonstrated better uptake of HBPE-NPs pre-treated with VS3-6 over polyethylene glycol (PEG)-HBPE-NPs, a standard NP surface modification. The uptake of VS5 pre-treated HBPE-NPs by monocytic cells (THP-1) was decreased over PEG-HBPE-NPs. VS5-treated HBPE-NPs delivered a cancer drug more efficiently and displayed better in vivo distribution over controls, remaining stable even after interacting with endothelial cells. Using a proteomics approach, proteins absorbed from sera-treated HBPE-NPs were identified, such as thrombospondin-1 (TSP-1), that could bind multiple cancer cell receptors. Our findings indicate that serum collected during an immune response to infection is a rich source of macromolecules that are absorbed by NPs and modulate their biological identity, achieving rationally designed uptake by targeted cell types.

Chaperonin containing TCP-1 (CCT/TRiC) is a novel therapeutic and diagnostic target for neuroblastoma

Chaperonin containing TCP1 (CCT/TRiC) is a multi-subunit protein folding complex that enables the cancer phenotype to emerge from the mutational landscape that drives oncogenesis. We and others linked increased expression of CCT subunits to advanced tumor stage and invasiveness that inversely correlates with cancer patient outcomes. In this study, we examined the expression of the second CCT subunit, CCT2, using genomic databases of adult and pediatric tumors and normal tissues, and found that it was highly expressed in pediatric cancers, showing a significant difference compared to normal tissues. Histologic staining confirmed that CCT subunits are highly expressed in tumor tissues, which was exemplified in neuroblastoma. Using two neuroblastoma cells, MYCN-amplified, IMR-32 cells, and non-amplified, SK-N-AS cells, we assessed baseline levels for CCT subunits and found expressions comparable to the highly invasive triple-negative breast cancer (TNBC) cell line, MDA-MB-231. Exogenous expression of CCT2 in both SK-N-AS and IMR-32 cells resulted in morphological changes, such as larger cell size and increased adherence, with significant increases in the CCT substrates, actin, and tubulin, as well as increased migration. Depletion of CCT2 reversed these effects and reduced cell viability. We evaluated CCT as a therapeutic target in IMR-32 cells by testing a novel peptide CCT inhibitor, CT20p. Treatment with CT20p induced cell death in these neuroblastoma cells. The use of CCT2 as a biological indicator for detection of neuroblastoma cells shed in blood was examined by spiking IMR-32 cells into human blood and using an anti-CCT2 antibody for the identification of spiked cancer cells with the CellSearch system. Results showed that using CCT2 for the detection of neuroblastoma cells in blood was more effective than the conventional approach of using epithelial markers like cytokeratins. CCT2 plays an essential role in promoting the invasive capacity of neuroblastoma cells and thus offers the potential to act as a molecular target in the development of novel therapeutics and diagnostics for pediatric cancers.

Synthesis, Enzymatic Degradation, and Polymer-Miscibility Evaluation of Nonionic Antimicrobial Hyperbranched Polyesters with Indole or Isatin Functionalities

Most macromolecular antimicrobials are ionic and thus lack miscibility/compatibility with nonionic substrate materials. In this context, nonionic hyperbranched polyesters (HBPs) with indole or isatin functionality were rationally designed, synthesized, and characterized. Antimicrobial disk diffusion assay indicated that these HBPs showed significant antibacterial activity against 8 human pathogenic bacteria compared to small molecules with indole or isatin groups. According to DSC measurements, up to 20% indole-based HBP is miscible with biodegradable polyesters (polyhydroxybutyrate or polycaprolactone), which can be attributed to the favorable hydrogen bonding between the N–H moiety of indole and the C=O of polyesters. HBPs with isatin or methylindole were completely immiscible with the same matrices. None of the HBPs leaked out from plastic matrix after being immersed in water for 5 days. The incorporation of indole into HBPs as well as small molecules facilitated their enzymatic degradation with PETase from Ideonella sakaiensis, while isatin had a complex impact. Molecular docking simulations of monomeric molecules with PETase revealed different orientations of the molecules at the active site due to the presence of indole or isatin groups, which could be related to the observed different enzymatic degradation behavior. Finally, biocompatibility analysis with a mammalian cell line showed the negligible cytotoxic effect of the fabricated HBPs.

Polymeric Nanoparticles with a Sera-Derived Coating for Efficient Cancer Cell Uptake and Killing

Nanoparticle-mediated cancer drug delivery remains an inefficient process. The protein corona formed on nanoparticles (NPs) controls their biological identity and, if optimized, could enhance cancer cell uptake. In this study, a hyperbranched polyester polymer (HBPE) was synthesized from diethyl malonate and used to generate NPs that were subsequently coated with normal sera (NS) collected from mice. Cellular uptake of NS-treated HBPE-NPs was compared to PEGylated HBPE-NPs and was assessed using MDA-MB-231 triple-negative breast cancer (TNBC) cells as well as endothelial and monocytic cell lines. NS-treated HBPE-NPs were taken up by TNBC cells more efficiently than PEGylated HBPE-NPs, while evasion of monocyte uptake was comparable. NS coatings facilitated cancer cell uptake of HBPE-NPs, even after prior interaction of the particles with an endothelial layer. NS-treated HBPE-NPs were not inherently toxic, did not induce the migration of endothelial cells that could lead to angiogenesis, and could efficiently deliver cytotoxic doses of paclitaxel (taxol) to TNBC cells. These findings suggest that HBPE-NPs may adsorb select sera proteins that improve uptake by cancer cells, and such NPs could be used to advance the discovery of novel factors that improve the bioavailability and tissue distribution of drug-loaded polymeric NPs.

Hyperbranched Poly(ester-enamine) from Spontaneous Amino-yne Click Reaction for Stabilization of Gold Nanoparticle Catalysts

Hyperbranched polymers have garnered much attention due to attractive properties and wide applications, such as drug-controlled release, stimuli-responsive nano-objects, photosensitive materials and catalysts. Herein, two types of novel hyperbranched poly(ester-enamine) (hb-PEEa) were designed and synthesized via the spontaneous amino-yne click reaction of A₂ monomer (1, 3-bis(4-piperidyl)-propane (A_2a ) or piperazine (A_2b )) and B₃ monomer (trimethylolpropanetripropiolate). According to Flory's hypothesis, gelation is an intrinsic problem in an ideal A₂ +B₃ polymerization system. By controlling the polymerization conditions, such as monomer concentration, molar ratio and rate of addition, a non-ideal A₂ +B₃ polymerization system can be established to avoid gelation and to synthesize soluble hb-PEEa. Due to abundant unreacted alkynyl groups in periphery, the hb-PEEa can be further functionalized by different amino compounds or their derivates. The as-prepared amphiphilic PEG-hb-PEEa copolymer can readily self-assemble into micelles in water, which can be used as surfactant to stabilize Au nanoparticles (AuNPs) during reduction of NaBH₄ in aqueous solution. As a demonstration, the as-prepared PEG-hb-PEEa-supported AuNPs demonstrate good dispersion in water, solvent stability and remarkable catalytic activity for reduction of nitrobenzene compounds.

Pseudo-branched polyester copolymer: an efficient drug delivery system to treat cancer

In this study, a new hyperbranched polyester copolymer was designed using a proprietary monomer and diethylene glycol or triethylene glycol as monomers. The synthesis was carried out using standard melt polymerization technique and catalyzed by p-tolulenesulfonic acid. The progress of the reaction was monitored with respect to time and negative pressure, with samples being subjected to standard characterization protocols. The resulting polymers were purified using the solvent precipitation method and characterized using various chromatographic and spectroscopic methods including GPC, MALDI-TOF, and NMR. We have observed polymers with a molecular weight of 29 643 Da and 33 996 Da, which is ideal to be used as a drug delivery system. Thus, these polymers were chosen for further modification into folate-functionalized polymeric nanoparticles for the targeted treatment of cancer, in this case we have chosen prostate cancer cells as a model. We hypothesized that due to the 3D structure of the A2B monomer, we expect a pseudo-branched polymer that is globular in shape which will be ideal for drug carrying and delivery. We used a solvent diffusion method for the one-pot formulation of water-dispersable polymeric nanoparticles as well as theraputic drug (doxorubicin) encapsulation. The efficacy of this delivery system was gauged by treating LNCaP cells with the drug-loaded nanoparticles and assessing the results of the treatment. The results were analyzed by cytotoxicity (MTT) assays, drug release studies, and fluorescence microscopy. The experimental results collectively show a nanoparticle that was biocompatible, target-specific, and successfully initiated apoptosis in an in vitro prostate cancer model.

Novozym 435-Catalyzed Synthesis of Well-Defined Hyperbranched Aliphatic Poly(β-thioether ester)

A series of new hyperbranched aliphatic poly(β-thioether ester)s were prepared by the enzymatic ring-opening polycondensation of 1,4-oxathiepan-7-one (OTO) and AB2/ABB' comonomer with acid-labile β-thiopropionate groups. Two kinds of comonomers, methyl 3-((3-hydroxy-2-(hydroxymethyl)propyl)thio)propanoate (HHTP) and methyl 3-((2,3-dihydroxypropyl)thio)propanoate (DHTP), with different primary alcohols and secondary alcohols, were synthesized by thiol-ene click chemistry and thiol-ene Michael addition, respectively. Immobilized lipase B from Candida antarctica (CALB), Novozym 435, was used as the catalyst. The random copolymers were characterized by 1H-NMR, 13C-NMR, GPC, TGA, and DSC. All branched copolyesters had high molecular weights over 15,000 Da with narrow polydispersities in the range of 1.75-2.01 and were amorphous polymers. Their degradation properties under acidic conditions were also studied in vitro. The polymeric nanoparticles of hyperbranched poly(β-thioether ester)s were successfully obtained and showed good oxidation-responsive properties, indicating their potential for biomedical applications.

Orthogonally clickable hyperbranched polymers: effect of reactant size and polarity on core-functionalization of peripherally jacketed HBPs

Using an orthogonally clickable strategy, the accessibility of internal allyl groups in jacketed HBPs, bearing either PEG or docosyl peripheral segments, was shown to depend both on the size and relative polarity of the reactant thiol.

Targeting chaperonin containing TCP1 (CCT) as a molecular therapeutic for small cell lung cancer

Identifying new druggable targets is desired to meet the needs for effective cancer treatments. To this end, we previously reported the efficacy of a therapeutic peptide called CT20p that displays selective cytotoxicity through inhibition of a multi-subunit, protein-folding complex called Chaperonin-Containing TCP-1 (CCT). To investigate the role of CCT in cancer progression, we examined protein levels of CCT subunits in liver, prostate, and lung cancer using human tissue microarrays. We found that these cancers expressed higher levels of CCT2 as compared to normal tissues. Small cell lung cancer (SCLC) stood out as having statistically significant difference in CCT2. Higher levels of CCT2 in tumors from lung cancer patients were also associated with decreased survival. Using SCLC cell lines, we observed detectable amounts of CCT subunits and cells were susceptible to killing by CT20p. Treatment with CT20p, delivered to cells using polymeric nanoparticles, was cytotoxic to all SCLC cell lines, decreasing the levels of CCT client proteins like STAT3. In contrast, treatment with a STAT3 inhibitor was effective in one of the SCLC cell lines. While we found that CCT levels could vary in cell lines, normal tissues had low levels of CCT and minimal toxicity to liver or kidney function was observed in mice treated with CT20p. These results indicate that in SCLC, changes in CCT levels could be used as a biomarker for diagnosis and that targeting CCT for inhibition with CT20p is a promising treatment approach for those cancers such as SCLC that currently lack targeted therapeutics.

Targetable Clinical Nanoparticles for Precision Cancer Therapy Based on Disease-Specific Molecular Inflection Points

Novel translational approaches based on clinical modular nanoplatforms are needed in order to treat solid cancers according to their discrete molecular features. In the present study, we show that the clinical nanopharmaceutical Ferumoxytol, which consists of a glucose-based coat surrounding an iron oxide core, could identify molecular characteristics of prostate cancer, corresponding to unique phases of the disease continuum. By affixing a targeting probe for the prostate-specific membrane antigen on its surface, the nanopharmaceutical was able to assess the functional state of the androgen receptor pathway via MRI, guiding therapy and delivering it with the same clinical nanoparticle. In order to simultaneously inhibit signaling from key oncogenic pathways of more advanced forms of prostate cancer, a single-agent therapy for early stage disease to inhibit DNA replication, as well as combination therapy with two drugs co-retained within the nanopharmaceutical's polymeric coating, were tested and resulted in complete tumor ablation. Recalcitrant and terminal forms of the disease were effectively treated with a nanopharmaceutical delivering a combination that upregulates endoplasmic reticulum stress and inhibits metastasis, thereby showing that this multifunctional nanoplatform can be used in the clinic for patient stratification, as well as precision treatment based on the individual's unique disease features.

PSMA-Targeted Theranostic Nanocarrier for Prostate Cancer

Herein, we report the use of a theranostic nanocarrier (Folate-HBPE(CT20p)) to deliver a therapeutic peptide to prostate cancer tumors that express PSMA (folate hydrolase 1). The therapeutic peptide (CT20p) targets and inhibits the chaperonin-containing TCP-1 (CCT) protein-folding complex, is selectively cytotoxic to cancer cells, and is non-toxic to normal tissue. With the delivery of CT20p to prostate cancer cells via PSMA, a dual level of cancer specificity is achieved: (1) selective targeting to PSMA-expressing prostate tumors, and (2) specific cytotoxicity to cancer cells with minimal toxicity to normal cells. The PSMA-targeting theranostic nanocarrier can image PSMA-expressing cells and tumors when a near infrared dye is used as cargo. Meanwhile, it can be used to treat PSMA-expressing tumors when a therapeutic, such as the CT20p peptide, is encapsulated within the nanocarrier. Even when these PSMA-targeting nanocarriers are taken up by macrophages, minimal cell death is observed in these cells, in contrast with doxorubicin-based therapeutics that result in significant macrophage death. Incubation of PSMA-expressing prostate cancer cells with the Folate-HBPE(CT20p) nanocarriers induces considerable changes in cell morphology, reduction in the levels of integrin β1, and lower cell adhesion, eventually resulting in cell death. These results are relevant as integrin β1 plays a key role in prostate cancer invasion and metastatic potential. In addition, the use of the developed PSMA-targeting nanocarrier facilitates the selective in vivo delivery of CT20p to PSMA-positive tumor, inducing significant reduction in tumor size.

Design and Synthesis of New Sulfur-Containing Hyperbranched Polymer and Theranostic Nanomaterials for Bimodal Imaging and Treatment of Cancer

In this study, we have synthesized a new hyperbranched polyester polymer containing sulfur-pendants (HBPE-S) in the branching points. This HBPE-S polymer is composed of spherical shaped, aliphatic three-dimensional architecture with carboxylic acid groups on the surface. The presence of sulfur pendants in the polymeric cavities demonstrated important role in the effective encapsulation of Bi-DOTA complexes ([Bi] = 5.21 μM), when compared to the previously reported polymer without sulfur pendants (HBPE, [Bi] = 1.07 x 10-3 μM). Higher X-ray blocking capability and excellent X-ray contrast images were obtained from Bi-DOTA encapsulating HBPE-S polymeric nanoparticles when compared with that of HBPE nanoparticles. In addition, the HBPE-S polymer's spherical structure with amphiphilic cavities allow for the successful encapsulation of anti-tumor drugs and optical dyes, indicating suitable for delivery of wide-range of theranostic agents for cancer diagnosis and treatment. Therapeutic drug taxol encapsulating, folic acid decorated HBPE-S-Fol nanoparticles showed more than 80% of lung carcinoma cell death within 24 h of incubation. Cell viability and microscopic experiments also confirmed for the targeted delivery, thereby minimizing toxicity to healthy tissues. Taken together, new HBPE-S polymer and multimodal theranostic nanoplatforms were synthesized with enhanced X-ray blocking capability for the effective cancer targeting and treatment monitoring.

Combination Therapy of NSCLC Using Hsp90 Inhibitor and Doxorubicin Carrying Functional Nanoceria

K-RAS driven non-small-cell lung cancer (NSCLC) represents a major cause of death among smokers. Recently, nanotechnology has introduced novel avenues for the diagnosis and personalized treatment options for cancer. Herein, we report a novel, multifunctional nanoceria platform loaded with a unique combination of two therapeutic drugs, doxorubicin (Doxo) and Hsp90 inhibitor ganetespib (GT), for the diagnosis and effective treatment of NSCLC. We hypothesize that the use of ganetespib synergizes and accelerates the therapeutic efficacy of Doxo via ROS production, while minimizing the potential cardiotoxicity of doxorubicin drug. Polyacrylic acid (PAA)-coated cerium oxide nanoparticles (PNC) were fabricated for the targeted combination therapy of lung cancers. Using "click" chemistry, the surface carboxylic acid groups of nanoceria were decorated with folic acid to target folate-receptor-overexpressing NSCLC. As a result of combination therapy, results showed more than 80% of NSCLC death within 48 h of incubation. These synergistic therapeutic effects were assessed via enhanced ROS, cytotoxicity, apoptosis, and migration assays. Overall, these results indicated that the targeted codelivery of Doxo and GT using nanoceria may offer an alternative combination therapy option for the treatment of undruggable NSCLC.

Branched polyesters: Preparative strategies and applications

In the last 20years, the availability of precision chemical tools (e.g. controlled/living polymerizations, 'click' reactions) has determined a step change in the complexity of both the macromolecular architecture and the chemical functionality of biodegradable polyesters. A major part in this evolution has been played by the possibilities that controlled macromolecular branching offers in terms of tailored physical/biological performance. This review paper aims to provide an updated overview of preparative techniques that derive hyperbranched, dendritic, comb, grafted polyesters through polycondensation or ring-opening polymerization mechanisms.

Chaperonin Containing TCP-1 Protein Level in Breast Cancer Cells Predicts Therapeutic Application of a Cytotoxic Peptide

PURPOSE

Metastatic disease is a leading cause of death for patients with breast cancer, driving the need for new therapies. CT20p is a peptide previously discovered by our group that displays cancer-specific cytotoxicity. To design the optimal therapeutic use of the peptide, we identified the intracellular target of CT20p in breast cancer cells, correlating expression patterns of the target with susceptibility to CT20p.

EXPERIMENTAL DESIGN

Using polymeric nanoparticles to deliver CT20p, we assessed cytoskeletal changes, cell migration, adhesion, and viability in cells treated with the peptide. Protein pull-down experiments, coupled to mass spectrometry, enabled identification of the peptide's intracellular target. Biochemical and histologic techniques validated target identity in human cell lines and breast cancer tissue microarrays and revealed susceptibility patterns to CT20p.

RESULTS

Chaperonin containing TCP-1 (CCT) was identified as the intracellular target of CT20p. Cancer cells susceptible to CT20p had increased CCT, and overexpression of CCTβ, a subunit of the CCT complex, enhanced susceptibility to CT20p. Susceptible cells displayed reduced tubulin, a substrate of CCT, and inhibition of migration upon CT20p treatment. CCTβ levels were higher in invasive ductal carcinomas than in cancer adjacent tissues and increased with breast cancer stage. Decreased breast cancer patient survival correlated with genomic alternations in CCTβ and higher levels of the chaperone.

CONCLUSIONS

Increased CCT protein in breast cancer cells underlies the cytotoxicity of CT20p. CCT is thus a potential target for therapeutic intervention and serves as a companion diagnostic to personalize the therapeutic use of CT20p for breast cancer treatment. Clin Cancer Res; 22(17); 4366-79. ©2016 AACR.

Formation of long sub-chain hyperbranched poly(methyl methacrylate) based on inhibited self-cyclization of seesaw macromonomers

Well-defined hyperbranched PMMA almost without self-cyclization was obtained through a click reaction, facilitated by a high concentration, good solvent and disubstituted chain ends.

Multifunctional MRI/PET Nanobeacons Derived from the in Situ Self-Assembly of Translational Polymers and Clinical Cargo through Coalescent Intermolecular Forces

Novel multifunctional platforms are needed for oncology in order to assist physicians during surgery and chemotherapy. In the present study, we show that polymeric nanobeacons, consisting of the glucose-based polymer dextran, can be used to guide surgery and improve drug delivery. For imaging, the nanobeacons stably retained the positron emitter 89-zirconium and the MRI contrast agent gadolinium, without the need of a chelator. In addition to using them for PET imaging, the (89)Zr-nanobeacons guided the surgical resection of sentinel lymph nodes, utilizing their inherent Cerenkov luminescence. Through weak electrostatic interactions, the nanoparticles carried combinations of chemotherapeutics for the simultaneous inhibition of oncogenic pathways, resulting in enhanced tumor regression. The nanobeacons also allowed monitoring of drug release via MRI, through the quenching of the gadolinium signal by the coloaded drug, making them a new multifunctional theranostic nanotechnology platform for the clinic.

Overcoming concealment effects of targeting moieties in the PEG corona: controlled permeable polymersomes decorated with folate-antennae for selective targeting of tumor cells

In the context of diligent efforts to improve the tumor targeting efficiency of drug carriers, a shape-persistent polymersome which possess a pH-tunable membrane as well as folate targeting antennae is reported. The membrane of such polymersomes behaves as gate which undergoes "on" and "off" switches in response to pH stimuli. Thus, polymersomes can effectively prohibit the premature release of chemotherapeutic agents such as doxorubicin in physiological conditions, but promote drug release once they are triggered in the acidified endosomal compartment. Importantly, the folate moieties are installed on the surface of polymersomes as protruding antennae by doping the polymersomes with folate-terminated block copolymers designed to have longer PEG segments. Thereby, the folate moieties are freed from concealment and steric effects exerted by the dense PEG corona. The cellular uptake of the FA-antennae polymersomes by tumor cells is significantly enhanced facilitated by the freely accessible folate antennae; however, the normal cells record a low level of cellular uptake due to the stealth property of the PEG corona. Overall, the excellent biocompatibility, controlled permeability, targeted internalization, as well as selective cytotoxicity of such polymersomes set up the basis for properly smart carrier for targeted drug delivery.

One-pot synthesis of indolizine functionalized nanohyperbranched polyesters with different nano morphologies and their fluorescent response to anthracene

Two nanohyperbranched polyesters of HBPE–CIDA₁ (nanospheres) and HBPE–CIDA₄ (nanospindles) were synthesized. The HBPE–CIDA₄ was established to be a fluorescent sensor for anthracene.

Hyperbranched polymers: advances from synthesis to applications

This review summarizes the advances in hyperbranched polymers from the viewpoint of structure, click synthesis and functionalization towards their applications in the last decade.

Dawn of advanced molecular medicine: nanotechnological advancements in cancer imaging and therapy

Nanotechnology plays an increasingly important role not only in our everyday life (with all its benefits and dangers) but also in medicine. Nanoparticles are to date the most intriguing option to deliver high concentrations of agents specifically and directly to cancer cells; therefore, a wide variety of these nanomaterials has been developed and explored. These span the range from simple nanoagents to sophisticated smart devices for drug delivery or imaging. Nanomaterials usually provide a large surface area, allowing for decoration with a large amount of moieties on the surface for either additional functionalities or targeting. Besides using particles solely for imaging purposes, they can also carry as a payload a therapeutic agent. If both are combined within the same particle, a theranostic agent is created. The sophistication of highly developed nanotechnology targeting approaches provides a promising means for many clinical implementations and can provide improved applications for otherwise suboptimal formulations. In this review we will explore nanotechnology both for imaging and therapy to provide a general overview of the field and its impact on cancer imaging and therapy.

Revisiting 30 years of biofunctionalization and surface chemistry of inorganic nanoparticles for nanomedicine

In the last 30 years we have assisted to a massive advance of nanomaterials in material science. Nanomaterials and structures, in addition to their small size, have properties that differ from those of larger bulk materials, making them ideal for a host of novel applications. The spread of nanotechnology in the last years has been due to the improvement of synthesis and characterization methods on the nanoscale, a field rich in new physical phenomena and synthetic opportunities. In fact, the development of functional nanoparticles has progressed exponentially over the past two decades. This work aims to extensively review 30 years of different strategies of surface modification and functionalization of noble metal (gold) nanoparticles, magnetic nanocrystals and semiconductor nanoparticles, such as quantum dots. The aim of this review is not only to provide in-depth insights into the different biofunctionalization and characterization methods, but also to give an overview of possibilities and limitations of the available nanoparticles.

The CT20 peptide causes detachment and death of metastatic breast cancer cells by promoting mitochondrial aggregation and cytoskeletal disruption

Metastasis accounts for most deaths from breast cancer, driving the need for new therapeutics that can impede disease progression. Rationally designed peptides that take advantage of cancer-specific differences in cellular physiology are an emerging technology that offer promise as a treatment for metastatic breast cancer. We developed CT20p, a hydrophobic peptide based on the C terminus of Bax that exhibits similarities with antimicrobial peptides, and previously reported that CT20p has unique cytotoxic actions independent of full-length Bax. In this study, we identified the intracellular actions of CT20p which precede cancer cell-specific detachment and death. Previously, we found that CT20p migrated in the heavy membrane fractions of cancer cell lysates. Here, using MDA-MB-231 breast cancer cells, we demonstrated that CT20p localizes to the mitochondria, leading to fusion-like aggregation and mitochondrial membrane hyperpolarization. As a result, the distribution and movement of mitochondria in CT20p-treated MDA-MB-231 cells was markedly impaired, particularly in cell protrusions. In contrast, CT20p did not associate with the mitochondria of normal breast epithelial MCF-10A cells, causing little change in the mitochondrial membrane potential, morphology or localization. In MDA-MB-231 cells, CT20p triggered cell detachment that was preceded by decreased levels of α5β1 integrins and reduced F-actin polymerization. Using folate-targeted nanoparticles to encapsulate and deliver CT20p to murine tumors, we achieved significant tumor regression within days of peptide treatment. These results suggest that CT20p has application in the treatment of metastatic disease as a cancer-specific therapeutic peptide that perturbs mitochondrial morphology and movement ultimately culminating in disruption of the actin cytoskeleton, cell detachment, and loss of cell viability.

Environment-responsive nanophores for therapy and treatment monitoring via molecular MRI quenching

The effective delivery of therapeutics to disease sites significantly contributes to drug efficacy, toxicity and clearance. Here we demonstrate that clinically approved iron oxide nanoparticles (Ferumoxytol) can be utilized to carry one or multiple drugs. These so called ‘nanophores’ retain their cargo within their polymeric coating through weak electrostatic interactions and release it in slightly acidic conditions (pH 6.8 and below). The loading of drugs increases the nanophores’ transverse T2 and longitudinal T1 NMR proton relaxation times, which is proportional to amount of carried cargo. Chemotherapy with translational nanophores is more effective than the free drug in vitro and in vivo, without subjecting the drugs or the carrier nanoparticle to any chemical modification. Evaluation of cargo incorporation and payload levels in vitro and in vivo can be assessed via benchtop magnetic relaxometers, common NMR instruments or MRI scanners.

Hyperbranched polyester nanorods with pyrrolo[2,1-a]isoquinoline end groups for fluorescent recognition of Fe3+

Novel hyperbranched polyester nanorods HBPE-CICA₆ and HBPE-CICA₂ were obtained and used to establish a highly sensitive fluorescent sensor for Fe³⁺ ions.

Hyperbranched polyester hydrogels with controlled drug release and cell adhesion properties

Hyperbranched polyesters (HPE) have a high efficiency to encapsulate bioactive agents, including drugs, genes, and proteins, due to their globe-like nanostructure. However, the use of these highly branched polymeric systems for tissue engineering applications has not been broadly investigated. Here, we report synthesis and characterization of photocrosslinkable HPE hydrogels with sustained drug release characteristics for cellular therapies. These HPE can encapsulate hydrophobic drug molecules within the HPE cavities due to the presence of a hydrophobic inner structure that is otherwise difficult to achieve in conventional hydrogels. The functionalization of HPE with photocrosslinkable acrylate moieties renders the formation of hydrogels with a highly porous interconnected structure and mechanically tough network. The compressive modulus of HPE hydrogels was tunable by changing the crosslinking density. The feasibility of using these HPE networks for cellular therapies was investigated by evaluating cell adhesion, spreading, and proliferation on hydrogel surface. Highly crosslinked and mechanically stiff HPE hydrogels have higher cell adhesion, spreading, and proliferation compared to soft and complaint HPE hydrogels. Overall, we showed that hydrogels made from HPE could be used for biomedical applications that require spatial control of cell adhesion and controlled release of hydrophobic clues.

Surface hybrid self-assembly, mechanism, and crystalline behavior of a carboxyl-ended hyperbranched polyester/platinum complex

The self-assembly of hyperbranched polymers has attracted much attention because of their wide application. In this article, we report a new facile surface self-assembly method for a carboxyl-ended hyperbranched polyester/platinum complex (HTD-3-Pt) and obtain ordered structural microrods with a length of 10-20 μm and a width of 1 μm. The length and diameter of the self-assembled microrods could be increased to 300-600 μm and 4-5 μm, respectively, by hierarchical self-assembly. The main factors affecting the morphology of the self-assemblies, including temperature, time, solvent and solubility parameter, and relative humidity were discussed by transmission/reflection polarizing optical microscopy (TRPOM), SEM, and HRSEM. The indications for the coordination bond (-COOPt) included the appearance of a new peak at 1606 cm(-1) and its shifting to 1634 cm(-1) in the FT-IR spectra, the disappearance of the C 1s peak at about 288.6 eV, and the increase in the O 1s electron binding energy in the XPS spectra. Furthermore, an interesting crystal property of the HTD-3-Pt self-assemblies was discovered and confirmed by XRD. The study results from the surface self-assembly mechanism suggest that the coordination induction of the platinum ion play a key role in driving microphase separation between the intermolecular chains and end groups of the HTD-3-Pt to form the microrod self-assemblies. Another interesting finding was that HTD-3-Pt showed a higher catalytic activity for hydrosilylation than did a traditional homogeneous catalyst.

Gadolinium-encapsulating iron oxide nanoprobe as activatable NMR/MRI contrast agent

Herein we report a novel gadolinium-encapsulating iron oxide nanoparticle-based activatable NMR/MRI nanoprobe. In our design, Gd-DTPA is encapsulated within the poly(acrylic acid) (PAA) polymer coating of a superparamagnetic iron oxide nanoparticle (IO-PAA), yielding a composite magnetic nanoprobe (IO-PAA-Gd-DTPA) with quenched longitudinal spin-lattice magnetic relaxation (T(1)). Upon release of the Gd-DTPA complex from the nanoprobe's polymeric coating in acidic media, an increase in the T(1) relaxation rate (1/T(1)) of the composite magnetic nanoprobe was observed, indicating a dequenching of the nanoprobe with a corresponding increase in the T(1)-weighted MRI signal. When a folate-conjugated nanoprobe was incubated in HeLa cells, a cancer cell line overexpressing folate receptors, an increase in the 1/T(1) signal was observed. This result suggests that, upon receptor-mediated internalization, the composite magnetic nanoprobe degraded within the cell's lysosome acidic (pH 5.0) environment, resulting in an intracellular release of Gd-DTPA complex with subsequent T(1) activation. In addition, when an anticancer drug (Taxol) was coencapsulated with the Gd-DTPA within the folate receptor targeting composite magnetic nanoprobe, the T(1) activation of the probe coincided with the rate of drug release and corresponding cytotoxic effect in cell culture studies. Taken together, these results suggest that our activatable T(1) nanoagent could be of great importance for the detection of acidic tumors and assessment of drug targeting and release by MRI.

Rational development of a cytotoxic peptide to trigger cell death

Defects in the apoptotic machinery can contribute to tumor formation and resistance to treatment, creating a need to identify new agents that kill cancer cells by alternative mechanisms. To this end, we examined the cytotoxic properties of a novel peptide, CT20p, derived from the C-terminal, alpha-9 helix of Bax, an amphipathic domain with putative membrane binding properties. Like many antimicrobial peptides, CT20p contains clusters of hydrophobic and cationic residues that could enable the peptide to associate with lipid membranes. CT20p caused the release of calcein from mitochondrial-like lipid vesicles without disrupting vesicle integrity and, when expressed as a fusion protein in cells, localized to mitochondria. The amphipathic nature of CT20p allowed it to be encapsulated in polymeric nanoparticles (NPs) that have the capacity to harbor targeting molecules, dyes or drugs. The resulting CT20p-NPs proved an effective killer, in vitro, of colon and breast cancer cells, and in vivo, using a murine breast cancer tumor model. By introducing CT20p to Bax deficient cells, we demonstrated that the peptide's lethal activity was independent of endogenous Bax. CT20p also caused an increase in the mitochondrial membrane potential that was followed by plasma membrane rupture and cell death, without the characteristic membrane asymmetry associated with apoptosis. We determined that cell death triggered by the CT20p-NPs was minimally dependent on effector caspases and resistant to Bcl-2 overexpression, suggesting that it acts independently of the intrinsic apoptotic death pathway. Furthermore, use of CT20p with the apoptosis-inducing drug, cisplatin, resulted in additive toxicity. These results reveal the novel features of CT20p that allow nanoparticle-mediated delivery to tumors and the potential application in combination therapies to activate multiple death pathways in cancer cells.

Polímeros usados como sistemas de transporte de princípios ativos

Os diferentes sistemas de transporte têm evidenciado potencial terapêutico para uma grande variedade de princípios ativos, satisfazendo vários requisitos, como a prevenção da sua eliminação rápida do organismo, a redução da sua toxicidade sistêmica, a estabilização e a otimização do seu metabolismo, e o direcionamento específico ao local alvo e os mecanismos de defesa. No entanto, têm sido reconhecidos vários outros desafios associados à liberação específica do princípio ativo ao local alvo, pelo que, para ultrapassar os obstáculos químicos e biológicos, a seleção do polímero utilizado para a preparação do sistema de transporte é de importância crucial. O presente trabalho apresenta um relato sobre os principais polímeros naturais e sintéticos utilizados para a preparação de sistemas de transporte de princípios ativos in vivo.

Selective N-alkylation of β-alanine facilitates the synthesis of a poly(amino acid)-based theranostic nanoagent

The development of functional amino acid-based polymeric materials is emerging as a platform to create biodegradable and nontoxic nanomaterials for medical and biotechnology applications. In particular, facile synthetic routes for these polymers and their corresponding polymeric nanomaterials would have a positive impact in the development of novel biomaterials and nanoparticles. However, progress has been hampered by the need to use complex protection-deprotection methods and toxic phase transfer catalysts. In this study, we report a facile, single-step approach for the synthesis of an N-alkylated amino acid as an AB-type functional monomer to generate a novel pseudo-poly(amino acid), without using the laborious multistep, protection-deprotection methods. This synthetic strategy is reproducible, easy to scale up, and does not produce toxic byproducts. In addition, the synthesized amino acid-based polymer is different from conventional linear polymers as the butyl pendants enhance its solubility in common organic solvents and facilitate the creation of hydrophobic nanocavities for the effective encapsulation of hydrophobic cargos upon nanoparticle formation. Within the nanoparticles, we have encapsulated a hydrophobic DiI dye and a therapeutic drug, Taxol. In addition, we have conjugated folic acid as a folate receptor-targeting ligand for the targeted delivery of the nanoparticles to cancer cells expressing the folate receptor. Cell cytotoxicity studies confirm the low toxicity of the polymeric nanoparticles, and drug-release experiments with the Taxol-encapsulated nanoparticles only exhibit cytotoxicity upon internalization into cancer cells expressing the folate receptor. Taken together, these results suggested that our synthetic strategy can be useful for the one-step synthesis of amino acid-based small molecules, biopolymers, and theranostic polymeric nanoagents for the targeted detection and treatment of cancer.

Cell-specific, activatable, and theranostic prodrug for dual-targeted cancer imaging and therapy

Herein we describe the design and synthesis of a folate-doxorubicin conjugate with activatable fluorescence and activatable cytotoxicity. In this study we discovered that the cytotoxicity and fluorescence of doxorubicin are quenched (OFF) when covalently linked with folic acid. Most importantly, when the conjugate is designed with a disulfide bond linking the targeting folate unit and the cytotoxic doxorubicin, a targeted activatable prodrug is obtained that becomes activated (ON) within the cell by glutathione-mediated dissociation and nuclear translocation, showing enhanced fluorescence and cellular toxicity. In our novel design, folic acid acted as both a targeting ligand for the folate receptor as well as a quencher for doxorubicin's fluorescence.

Cytochrome C encapsulating theranostic nanoparticles: a novel bifunctional system for targeted delivery of therapeutic membrane-impermeable proteins to tumors and imaging of cancer therapy

The effective administration of therapeutic proteins has received increased attention for the treatment of various diseases. Encapsulation of these proteins in various matrices, as a method of protein structure and function preservation, is a widely used approach that results in maintenance of the protein's function. However, targeted delivery and tracking of encapsulated therapeutic proteins to the affected cells is still a challenge. In an effort to advance the targeted delivery of a functional apoptosis-initiating protein (cytochrome c) to cancer cells, we formulated theranostic polymeric nanoparticles for the simultaneous encapsulation of cytochrome c and a near-infrared dye to folate-expressing cancer cells. The polymeric nanoparticles were prepared using a novel water-soluble hyperbranched polyhydroxyl polymer that allows for dual encapsulation of a hydrophilic protein and an amphiphilic fluorescent dye. Our protein therapeutic cargo is the endogenous protein cytochrome c, which upon cytoplasmic release, initiates an apoptotic response leading to programmed cell death. Results indicate that encapsulation of cytochrome c within the nanoparticle's cavities preserved the protein's enzymatic activity. The potential therapeutic property of these nanoparticles was demonstrated by the induction of apoptosis upon intracellular delivery. Furthermore, targeted delivery of cytochrome c to folate-receptor-positive cancer cells was achieved via conjugation of folic acid to the nanoparticle's surface, whereas the nanoparticle's theranostic properties were conferred via the coencapsulation of cytochrome c and a fluorescent dye. Considering that these theranostic nanoparticles can carry an endogenous cellular apoptotic initiator (cytochrome c) and a fluorescent tag (ICG) commonly used in the clinic, their use and potential translation into the clinic is anticipated, facilitating the monitoring of tumor regression.

Ganoderic Acid DM: An Alternative Agent for the Treatment of Advanced Prostate Cancer

Prostate cancer is the most commonly diagnosed cancer in men and accounts for significant morbidity and mortality in the western world. While traditional therapies are effective at clearing early stage cancer, they often fail to treat late stage metastatic disease. Thus, an effective therapy that targets prostate tumor growth and metastasis is desired for alleviating the disease and improving patient outcomes. Natural extracts have been the focus of recent investigation, particularly those with reduced cellular toxicity to healthy tissue. In this review, we discuss one potential candidate, ganoderic acid, an extract from the Ganoderma lucidum mushroom that has been tested in multiple cancer models. Interestingly, ganoderic acid DM (GA-DM) has shown toxicity to both androgen-dependent and independent prostate cancer cells with reduced osteoclastogenesis in late stage metastatic disease. This review will discuss the current knowledge on this GA-DM extract and the potential benefit in treating advanced prostate cancer. We will also provide an overview on the targeted delivery of GA-DM through nanoparticles that would reduce bystander toxicity and improve the drug's effectiveness. An improved understanding of this drug and its uses will advance the field of natural chemotherapeutics, particularly in treating advanced prostate cancer.